Process of delustering acetone-soluble cellulose acetate textile with a hot soap solution containing hydrogen peroxide



3 031 254 PROCESS OF DELUST ERING ACETONE-SOLUBLE CELLULGSE ACETATETEXTILE WITH A HOT SOAP SOLUTION CONTAINING HYDROGEN EEROXIDE DennisGrady, Harold Bates, and James Wotherspoon Fisher, Spondon, near Derby,England, assignors to British Celanese Limited, a corporation of GreatBritain No Drawing. Filed Sept. 9, 1955, Ser. No. 533,506 Claimspriority, application Great Britain Oct. 1, 1954 3 Claims. (Cl. 8-431)This invention relates to the treatment of textile and other materialsof cellulose acetate for the purpose of effecting a reduction in theirlustre.

It is well known that the lustre of bright textile materials ofacetone-soluble cellulose acetate can be reduced by subjecting thematerial to a suitable hot aqueous treatment. For this purpose treatmentwith an aqueous soap solution at or near the boil is largely employedcommercially. The ease with which loss of lustre takes place variessomewhat according to the particular acetonesoluble cellulose acetate ofthe material. Some materials lose lustre relatively easily and can begiven a more or less completely mat appearance by a treatment for 1 /2hours in a 5 gram per litre soap solution at 99 C. Others are somewhatless delustred by such a treatment but have the advantage that when abright finish is required they can readily be dyed in the soap bathsconventionally used for dyeing cellulose acetate at temperatures up toperhaps 85 C. with little risk of loss of lustre.

Various substances have been proposed for addition to the aqueous soapbaths in order to accelerate the delustring action of the latter or topermit a greater reduction of lustre. Examples of such substances arephenol, pine oil, methylcyclohexanol, terpineol and naphthalene but noneare entirely satisfactory. Some are not effective to a worthwhileextent, some add unreasonably to the cost of the process, some result ina very considerable loss in the strength of the material while some, forexample phenol and naphthalene, are difficult to remove to the extentnecessary if the material is not to have an unwanted odour.

We have now found that hydrogen peroxide can be used to increase thedelustring action of hot aqueous delustring liquids on textile and othermaterial of acetonesoluble cellulose acetate. The material may besubjected to the action of the hydrogen peroxide before the terminationof delustring by the liquid. Thus we have found that material which hasbeen treated with aqueous hydrogen peroxide, for example hydrogenperoxide in aqueous soap solution at 65 (3., loses lustre more rapidlythan the untreated material when it is subjected to an aqueous soapsolution at or near the boil. We have obtained the best results howeverby simply including hydrogen peroxide in the hot aqueous delustring bathitself. Thus by treatment at or near the boil (97 to 100 C.), e.g. at 99C., for 1 /2 hours in a 5 grams per litre soap solution to which hasbeen added 1 cc. per litre of hydrogen peroxide (130 volumes) a fulldelustre can be obtained on a bright cellulose acetate yarn or fabric,eg a satin fabric, which is only partially delustred by a similartreatment omitting the hydrogen peroxide.

The use of hydrogen peroxide in this way results in a product ofacceptable strength and does not impart unwanted odour. Further, thematerial is simultaneously bleached so that a separate bleachingoperation is unnecessary.

The preferred delustring bath is an aqueous soap solution containingabout 5 grams of soap per litre. Hydrogen peroxide is however aneffective delustring accelerator for lower or higher concentrations ofsoap, e.g. con- Fatented Apr. 24, 1962 centrations down to 1 or 2 gramsper litre or up to 8 or 10 grams per litre.

The concentration of hydrogen peroxide in the soap solution may varywithin quite wide limits. Excellent results can be obtained by usingfrom 1 to 5 ccs. per

liter of hydrogen peroxide volumes). Lower concentrations can be used,for example 0.75 cc. per litre and satisfactory results obtained, butconcentrations as low as 0.5 cc. per litre generally lead to decidedlyinferior results.

The hydrogen ion concentration of the delustring bath is of someimportance for best results. We find that the delustring efiectincreases as the pH value of the bath increases from about 7.0 to about9.5 but at higher pH value tends to fall off somewhat. It is preferredto effect the delustring treatment at a pH value of 8.5 to 9.

In the case of treating cellulose acetate fabric it is preferred toapply the treatment to material which is substantially free from size. Asoap delustring bath may then be used a number of times if hydrogenperoxide is added, after each batch of material has been treated, tobring the concentration of hydrogen peroxide back to the desired level.The hydrogen peroxide initially present is by no means all decomposedduring a delustring treatment of 1 /2 hours at 99 C. If desired,however, the treatment may be applied to cellulose acetate fabricscarrying the weaving size, the treatment then serving both to removesize from the material and to effect delustring. In this case it ispreferred to use a fresh soap bath for each batch of material sinceotherwise size and other products accumulate in the bath and appear todiminish the delustring action. If desired, after delustring thematerial in the manner described, it may be given a scouring treatment,for example with an alkali metal salt of a long chain alkyl sulphatetype of detergent, for the purpose of removing any unwanted fatty acidor difficultly soluble metallic soap from the material.

While the process can be used for the treatment of cellulose acetateyarns it is of most value for the treatment of fabrics. The latter maybe subjected to the action of the delustring bath in any convenient way,for example by suspending them in the form of hanks of fabric in thedelustring liquor.

It is surprising that the hydrogen peroxide is so efiec tive inaccelerating the delustring action of the hot aqueous liquids onacetone-soluble cellulose acetate since we find that other oxidisingbleaching agents seem to have little effect or very much less effect onthe rate of delustring. This applies for instance to sodium percarbonateand to sodium hypochlorite.

We do not exclude the use of hydrogen peroxide produced in thedelustring bath by suitable means.

Aqueous solutions of detergent cationic or anionic surface-active agentsother than sodium or other alkali metal soaps of fatty acids maylikewise have their delustring action increased by means of hydrogenperoxide. Such surface-active agents may be quaternary ammoniumcompounds (in the form of water-soluble salts) containing anunsubstituted alkyl group having a chain of at least 10 successivecarbon atoms united by carbon to carbon linkages, for examplecetyl-trimethyl-ammonium chloride or bromide. Again they may be acidsulphates or acid phosphates (in the form of water-soluble salts) ofmonohydroxylated aliphatic hydrocarbons having a chain of at least 10successive carbon atoms united by carbon to carbon linkages countingfrom and including the carbon atom carrying the hydroxyl group, forexample lauryl sulphate, palmityl sulphate, stearyl sulphate, or olelylsulphate, or the sulphate of a mixture of such alcohols as can beobtained by reduction of the esters of the mixture of fatty acids foundin cocoanut oil. Detergent of the alkylarylsulphonate type may likewisebe employed. Such surface-active agents are, however, generally inferiorto soaps as delustring agents for cellulose acetate and when used in thepresence of hydrogen peroxide are likewise inferior to aqueous solutionsof soap used in the presence of hydrogen peroxide.

The invention is illustrated by the following example:

Example A loom state satin fabric consisting entirely of yarns ofacetone-soluble cellulose acetate of a kind which cannot be completelydelustred by treatment for 1 /2 hours in a 5 grams per litre soapsolution at 99 C., is desized by a treatment for /2 hour at 85 C. in a 5grams per litre solution of soap-flakes in water. The de-sized material,in the form of a hank, is then immersed in an aqueous bath containing 5grams per litre of soap-flakes and 1 cc. per litre of hydrogen peroxide(130 volumes). The temperature of the bath is then raised to 99 C. andis maintained at this for 1 /2 hours, the hank of fabric being turned atintervals to ensure even treatment. The material is then lifted from thedelustring bath and scoured at 65 C. for 30 minutes in an aqueous bathcontaining per liter 2 cc. of ammonia and 0.2 gram of Pentrone T, afatty alcohol sulphate. This operation may be carried out on a winch.Finally the material is washed oil, hydro-cxtracted and dried on a pinstenter.

The fabric is thus given a dull finish which is much duller than isobtained if the delustring operation is effected with aqueous soapsolution only without the addition of hydrogen peroxide.

Though the invention is primarily of value in the delustring of textilematerial of acetone-soluble cellulose acetate, it may be used inconnection with the delustring of textile material of other types ofcellulose acetate *2: which are susceptible to reduction of lustre byhot aqueous treatments, for example to textile materials of this kind ofwhich the cellulose acetates are of acetyl values ranging up to that ofa cellulose triacetate. The new process may also be applied for thedelustring of cellulose acetate in other forms, .for example foils orfilms of acetone soluble cellulose acetate.

Having described our invention what we desire to secure by LettersPatent is:

1. In a process wherein textile material of acetonesoluble celluloseacetate is delustred by the action of a hot aqueous solution of soap thesolution having a pH value of 7 to 9.5, increasing the delustring actionof the solution by including hydrogen peroxide therein in an amount perlitre equivalent to from 1 to 5 ccs. of hydrogen peroxide of 130 volumestrength.

2. Process according to claim 1 in which said hot aqueous solution ofsoap has 1 to 10 grams of soap per litre and is at a temperature of 97to 100 C.

3. Process according to claim 1 in which said hot aqueous solution ofsoap has about 5 grams of soap per litre, a pH of 8.5 to 9 and atemperature of 97 to 100 C. in which said treatment has a duration ofabout 1 /2 hours and in which said solution contains per litre hydrogenperoxide equivalent to about 1 cc. of hydrogen peroxide of volumestrength.

References Cited in the file of this patent UNITED STATES PATENTS2,264,415 Taylor Dec. 2, 1941 FOREIGN PATENTS 388,520 Great Britain Mar.2, 1933 394,333 Great Britain June 21, 1938

1. IN A PROCESS WHEREIN TEXTILE MATERIAL OF ACETONESOLUBLE CELLULOSEACETATE IS DELUSTRED BY THE ACTION OF A HOT AQUEOUS SOLUTION OF SOAP THESOLUTION HAVING A PH VALUE OF 7 TO 9.5, INCREASING THE DELUSTRING ACTIONOF THE SOLUTION BY INCLUDING HYDROGEN PEROXIDE THEREIN IN AN AMOUNT PERLITRE EQUIVALENT TO FROM 1 TO 5 CCS. OF HYDROGEN PEROXIDE OF 130 VOLUMESTRENGTH.